#2 cylinder won't fire

[loungeguy69]

'82 1100E. Has been sitting idle for nearly two years. Cleaned the tank and petcock. Tore down the carbs and they're spotless. Adjusted the valves and pre-lubed the cams. Changed the oil. Cleaned and gapped the plugs. Charged the battery.

The engine will run but only on three cylinders. The wet plug in #2 cylinder says that's the culprit. I checked the plug wires and they're ok. I even swapped #2 and #3 wires over to see if the coil had a bad terminal. The plug continuity checks ok.

When rev'ed the engine produces thick white smoke and sputters. There isn't any evidence that the missing cylinder is even firing occasionally.

Am I missing something (before I get savaged by mosquitos in the sweat lodge aka garage)?

[Dave8338]

Have you checked for spark on that plug/wire combo? Is your vacuum line for the petcock filled with fuel? It does attach to the #2 carb, correct?

[dr_fosg8]

Agreed...check the vacuum line for the petcock. Mine connected to #2 and I had the same problem.

Try disconnecting the vac. line and plugging it, then try running on prime.

[tone]

If #2 plug is sparking & you are sure the carbs are as clean as they are ever going to get, the float heights & jets are correct than i guess your next thing to do is a compression check

[loungeguy69]

I haven't checked the vaccum line. When I cleaned the petcock I didn't replace the o-rings and diaphragm, I just cleaned them. It seemed to work ok using the blow/suck test. Is fuel in the vacuum line a symptom of a half-assed petcock rebuild?

[loungeguy69]

If #2 plug is sparking & you are sure the carbs are as clean as they are ever going to get, the float heights & jets are correct than i guess your next thing to do is a compression check

The bike ran fine before. i.e. Compression was good, etc. The plug doesn't show signs of oil burnoff. I wondered about valve oil seals being dried and cracked. Could the compression go south from just sitting?

[dr_fosg8]

Sub-par rebuild is not always the case. Many members here have tried to rebuild them with no luck. Doesn't always work for some reason.

A new petcock is available here. http://www.mrcycles.com/default.asp

Or from your local dealer. Mine was about 60 bucks.

Try plugging the vacuum line and taking a ride on prime after cleaning the plug or changeing and see if there is any difference.

[loungeguy69]

Agreed...check the vacuum line for the petcock. Mine connected to #2 and I had the same problem.

Try disconnecting the vac. line and plugging it, then try running on prime.

What might cause the vacuum line to fill with fuel?

I'm all over this post like a cheap suit. I'm frustrated and have been really looking forward to rolling away on my baby. Thanks for the feedback so far.

[dr_fosg8]

If the diaphram inside the petcock that seals the vacuum side from the fuel side is leaking it will allow fuel to pass into the vacuum line making #2 carb massivly rich.

[tone]

The bike ran fine before. i.e. Compression was good, etc. The plug doesn't show signs of oil burnoff. I wondered about valve oil seals being dried and cracked. Could the compression go south from just sitting?

After 2 years of sitting unused the rings may be stuck, there may have been a little moisture get into the bore (least one valve will have been open) a little moisture could cause some corrosion to bore rings or valve seats the only way to get an idea without stripping it is to do the test mate

[Hoges]

I've had the same thing happen to me recently with number 1 cylinder. Checked spark and plug was wet,but then I sprayed some WD40 onto the carb intake boots at the aircleaner and bang off she went again, running on four. Checked and sure enough there was a leaking intake boot from the cleaner to the carb body. Maybe yours is the same problem..........

[Baatfam]

What might cause the vacuum line to fill with fuel?

If the diaphram is leaking the fuel will enter the vacumn line....
Pull the line off the carb, cap off the vacumn port and try it on prime...
If it runs good then, your petcock is the problem...

[loungeguy69]

I've had the same thing happen to me recently with number 1 cylinder. Checked spark and plug was wet,but then I sprayed some WD40 onto the carb intake boots at the aircleaner and bang off she went again, running on four. Checked and sure enough there was a leaking intake boot from the cleaner to the carb body. Maybe yours is the same problem..........

Already checked the boots for that exact reason. Sprayed WD40 on both ends and no difference. Not even a subtle change in revs so that's not the problem. I reassemble with a smear of petroleum jelly just for that reason.

[loungeguy69]

If the diaphram is leaking the fuel will enter the vacumn line....
Pull the line off the carb, cap off the vacumn port and try it on prime...
If it runs good then, your petcock is the problem...

I will do this. The diaphragm looked ok when I cleaned it although a bit of black 'skin' came off during cleaning. Perhaps it's now porous..?